Vane pump or motor

ABSTRACT

A vane pump or motor having a rotatable cylindrical disc incorporated in a housing. The disc has radial grooves provided with radially movable vanes. The housing has at least one pair of associated inlet and outlet apertures, and the part of the inner wall of the housing situated between said apertures is cylindrical and has a larger diameter than the disc. The inner wall between the apertures also forms a boundary for a working space. The number of vanes in a disc is relatively large so that at least two vanes are present between an inlet aperture and an associated outlet aperture.

United States Patent [72] Inventor Hillebrand Johannes JosephusKraaltman Emmasingel, Eindhoven, Netherlands [21] Appl. No. 858,411 [22]Filed Sept. 16, 1969 [45] Patented Dec. 7, 1971 [73] Assignee U.S.Philips (Iorporation New York, N .Y. [32] Priority Sept. 18, 1968 [3 3]Netherlands [31] 6813309 [54] VANE PUMP 0R MOTOR 1 Claim, 3 DrawingFigs.

[52] U.S. Cl 418/266 [51] Int. Cl Flllc' 1/00, F03c 3/00, F040 H00 [50]Field of Search 418/241, 15, 138,266, 157,268; 103/136 R;9l/124, 121,135

[56] References Cited UNlTED STATES PATENTS 2,371,081 3/1945 Tucker eta1 418/268 X Primary Examiner-Carlton R. Croyle Assistant Examiner-R. E.Gluck Al!0rney-Frank R. Trifari ABSTRACT: A vane pump or motor having arotatable cylindrical disc incorporated in a housing. The disc hasradial grooves provided with radially movable vanes. The housing has atleast one pair of associated inlet and outlet apertures, and the part ofthe inner wall of the housing situated between said apertures iscylindrical and has a larger diameter than the disc. The inner wallbetween the apertures also forms a boundary for a working space. Thenumber of vanes in a disc is relatively large so that at least two vanesare present between an inlet aperture and an associated outlet aperture.

PAIENTEDHEB 71971 $626,265

SHEET 1 UF 2 VANE PUMP R MOTOR This invention relates generally to avane pump or vane motor. Specifically it comprises a cylindrical,rotatable disc accommodated in a housing surrounding the disc. The discis provided with the disc a number of radial grooves which are regularlydistributed about its circumference and extend in the axial direction.The grooves support herein radially movable vanes which, have theirends, remote from the disc, guided by the inner wall of the housing. Thehousing is provided with at least one pair of inlet and outlet aperturesassociated with each other for the passage of a fluid. The part of theinner wall of the. housing situated between each associated pair ofinlet and outlet apertures is cylindrical and has a larger diameter thanthe disc, and forms a boundary for a working space.

A vane pump or motor of the above-described type is known from DutchPat. specification No. 102,292. In this known vane pump or motor thegrooves are arranged at such regular distances from each other that thedistance between the adjacent vanes, measured on a circle the diameterof which corresponds to that of the cylindrical wall part of the housingwhich bounds a working space, is substantially equal to the dimension ofsaid wall part viewed in the direction of its circumference. In such apump or motor only one vane produces a seal between the inlet and theoutlet. At the instant this one vane leaves the relative cylindricalwall part, a subsequent vane will contact said wall part. The result ofthis is that the differential pressure across the first vane must beimmediately assumed by the next vane. It has been found that this suddentaking over of the full differential pressure-of one vane by the nextproduces certain disturbances in the operation of the pump or motor. Ina motor, it is a disturbance in the number of revolutions and in a pumpa disturbance in the supply of liquid. In case where a high degree ofaccuracy in the number of revolutions (for example, in driving precisionmachine tools) and in the supply of liquid (uniform supply withoutpressure ripples) is required, these disturbances are highlyobjectionable.

The present invention is based on the recognition of the fact that sucha disturbance is caused as a result of a vane being tilted backwards" inits groove due to the friction contact with the inner wall of thehousing, viewed in the direction of revolution of the disc when there isno pressure difference across it. When such a vane contacts the wallpart which forms a boundary of a working space, and the preceding vaneleaves said wall part, the differential pressure will be across the vanewhich has just contacted said wall part. As a result of the prevailingpressure differential, the vane flips in its groove so that, viewed inthe direction of revolution of the disc, itassumes a tilted forward"position in the groove. During; this flipping the seal between'the inletand the outlet is momentarily broken thereby resulting. in theabove-mentioned disturbance.

It is accordingly an object of the invention to provide avane pump ormotor in which the disturbances of prior devices is fully avoided.

The vane pump or motor according to the invention is characterized inthat the grooves in the disc are regularlydistributed about itscircumference in such a. manner that the angle enclosed by radial planespassing through the center of two adjacent grooves and the axis of thedisc is at most equal to half of the angle enclosed by two planes eachpassing through the axis of the disc and one of which passes through theend of the wall part of the housing bounding a working space adjacent tothe inlet aperture and the other passes through the end of said wallpart adjacent the outlet aperture.

In this manner a motor or pump is obtained in which two vanes willalways contact the wall part of the housing which forms a boundary forthe working space so that the seal between the inlet and the outlet isalways ensured by two vanes arranged in series. The result of this isthat the flipping over of a vane occurs when the succeeding vane in thedirection of drum rotation has already flipped over so that no bypasssituation or open communication between inlet and outlet, will occur. Ithas been found that the disturbance in the number of revolutions and thesupply of liquid, found in prior devices, is avoided in the motor orpump of the present invention.

Since twosealing vanes are always present between an inlet and anassociated outlet aperture, the contraction and expansion of the liquidin.the parts of the working space communicating with the inlet andoutlet, respectively, also becomes much more gradual. It will be obviousthat this also contributes to a disturbance-free running of the motorand the pump, respectively.

In a further favorable embodiment,,each cylindrical wall part whichbounds aworking space is provided, at its ends adjacent the inlet andoutlet apertures, with equal circumferentially extendingdischarge-grooves. The grooves extend over a distance equal tothe arclengthtof the cylindrical wall part diminished by twice the distancebetween the vanes measured on .the same diameter as that of therelativewall part in such manner that the resistance to flow across a vane whichis incontact withia track of the wall part, in which the dischargegrooves are situated, is substantiallyequal to .half the resistance toflow across a vane which is in contact with the track of thewall part inwhich no discharge grooves are situated. As aresult of this thecontraction and expansion, respectively, of liquid in the parts of theworking space which communicate with the inlet and outlet occurs evenmore gradually I while the total resistance to flowbetween the inlet andoutlet is always the same so that avoidance of the objectionabledisturbances is further insured.

In order that the invention may be readily carried into effect oneembodiment thereof will now be described in greater detail, byway ofexample, with reference to the accompanying drawings, in which FIGS. 1and 2.show two cross-sectional views at mutually right angles of a vanemotor having two working spaces, and

FIG. 3 shows a workingspace of the motor shown in FIG. I and FIG. 2 onanenlarged scale.

In FIGS. land 2, reference numeral 1 denotes a cylindrical disc. Thisdisc is provided on its circumference with anumber of regularly spacedradial, grooves 2. The grooves 2 have radially movable vanes 3. The disc1 is surrounded by a housing 4 having a pair of associated inlet andoutletports 5 and 6 and a pair of associated inlet and outlet ports 7and 8. The housing 4 is closed at its ends by covers 9 and 10 in whichthe shaft ll of the disc is joumaled in a sealing manner.

The inner wall of the housing 4 surrounds the disc in such a manner thattogether with the flanges 12 and 13 arranged on the disc two workingspaces 14 and 15 are formed. The parts 16 and 17 of the inner wall ofthe housing 4 between the inlet ports Sand 7 and the associated outletports 6 and 8 are concentric with the disc but situated at a largerdiameter while the parts 18 and 19 of the inner wall of the housingsituated between the outlet ports 8 and 6 andthe inlet ports 5 and 7cooperate, in a sealing manner with the disc I.

The number of grooves 2 and vanes 3 movable therein is chosen to. besuch that each angle 11: enclosed by two radial surfaces passing throughthe axis and through the center of two adjacent grooves is smaller thanhalf of the angle il enclosed by a plane through the axis and throughthe end of the wall parts t 16 and 17,, respectively, which adjoins theinlet ports 5 and 7, respectively, and a plane through the axis andthrough. theend of the wall parts 16. and 17, respectively, whichadjoins the outlet ports 6 and 8, respectively.

In this manner at least two vanes are always in contact with each of thewall parts 16 and 17 so that the sealing between theinlet and outlet isalways ensured by at least two vanes.

FIG. 3 shows the working space 14 on an enlarged scale. From this Figureis appears that when the vane 20 leaves the wall part 16, the vane 22already contacts the wall part 16. In the inlet 5 and in the part 23 ofthe working space substantially the same high pressure prevails. So nodifferential pressure prevails across the vane 22 and as a result of thefriction between said vane and the wall 16 said vanewill assume a tiltedbackwards position (viewed in the direction of revolution of the disc1). In the part 24 of the working space the pressure will have droppeddue to leakage so that a differential pressure does occur across thevane 21 so that said vane (see drawing) is tilted forwards. A lowpressure prevails in the outlet 6 so that the vane 20 is also tiltedforwards.

When the disc 1 is further rotated, the space 24 comes in opencommunication with the outlet 6. The vane 21 will remain in itsforward-tilted position as shown. The pressure in the space 23 willdrop, the vane 22 flipping from its backwards-tilted position toits'forward'tilted position. During this flipping over a considerableleak occurs for a moment across the vane 22 but since the vane 21 doesnot flip and remains in the sealing position, no liquid can flow fromthe high-pressure inlet to the low-pressure outlet. Therefore, no bypasssituation will occur each time a vane flips over, in other words opencommunication between the inlet is avoided and the outlet. This resultsin a vane motor which operates without disturbances (very constantnumber of revolutions). When used in a vane pump, a uniform supply ofliquid without, pressure ripples, is produced.

In order to insure that the overall resistance to flow between the inlet5 and the outlet 6 is always the same, the wall part 16, at the area ofits communication with the inlet and outlet, is provided with a numberof discharge grooves 26 and 27 extending in the circumferentialdirection. The length of said discharge grooves is equal to the lengthof the wall part 16 diminished by the distance between the vanes 20 and22 so that when the vane 22 contacts the wall part 16, the vane 20 justarrives in the track provided with discharge grooves 27 while at theinstant at which the vane 20 leaves the wall part 16, the vane 22 justpasses the end of the discharge groove 26. The discharge grooves areconstructed so that the resistance to flow across each of the vanes 20and 22, when these are in the position shown in F 10. 3, is exactly halfof the resistance to flow across the vane 21. In this manner the overallresistance to flow between the inlet and outlet will always be the same.Upon variation of this resistance to flow the number of revolutionswould also vary. This is fully avoided by the existence of dischargegrooves 26 and 27.

The discharge grooves 26 and 27 also provide that the expansion of theliquid from the space 24 (in a pump contraction of liquid) in the outletoccurs much more gradually, which is also favorable for a number ofrevolutions which is as constant as possible.

Although the drawing shows by way of example a vane motor, it will beobvious that the invention can be applied with the same advantages to avane pump.

Furthermore it is to be noted that the invention can be applied to vanemotors and pumps having any number of working spaces, the onlyrequirement being that at least two sealing vanes be present between aninlet and an associated outlet.

What is claimed is:

l. A vane pump or motor comprising a cylindrical disc rotatably arrangedin a housing surrounding it, said disc having a plurality of radialgrooves extending in the axial direction and regularly distributed onits circumference, said grooves being provided with radially movablevanes which, with their ends remote from the disc are guided by theinner wall of the housing, said vanes being arranged for pivotalmovement within said grooves, said housing comprising at least one pairof associated inlet and outlet apertures for liquid, and means producingpressure difference across said vanes, the part of the inner wall of thehousing situated between each pair of associated inlet and outletapertures being cylindrical and having a larger diameter than the disc,said wall part also forming a boundary for a working space, said groovesin the disc being regularly distributed about the circumference thereofin such manner that the angle enclosed by radial planes passing throughthe center of two adjacent grooves and the axis of the disc is equal tono greater than half of the angle enclosed by two planes each passingthrough the axis of the disc and one of which passes through the end ofthe wall part of the housing forming the boundary of the working spacewhich communicates within the inlet aperture and the other passesthrough the end of said wall part which communicates with the outletaperture, equal discharge grooves provided on each cylindrical wall partwhich forms a boundary for a working space communicating at its endswith inlet and outlet apertures, said discharge grooves extending in thecircumferential direction over a distance equal to the arc length of thecylindrical wall part diminished by twice the distance between the vanesmeasured on the same diameter as that of the relative wall part, saidgrooves being arranged so that when a vane passes thereacross theresistance to flow across said vane is substantially equal to half theresistance to flow across a vane which contacts the track of the wallpart in which no discharge grooves are arranged.

1. A vane pump or motor comprising a cylindrical disc rotatably arrangedin a housing surrounding it, said disc having a plurality of radialgrooves extending in the axial direction and regularly distributed onits circumference, said grooves being provided with radially movablevanes which, with their ends remote from the disc are guided by theinner wall of the housing, said vanes being arranged for pivotalmovement within said grooves, said housing comprising at least one pairof associated inlet and outlet apertures for liquid, and means producingpressure difference across said vanes, the part of the inner wall of thehousing situated between each pair of associated inlet and outletapertures being cylindrical and having a larger diameter than the disc,said wall part also forming a boundary for a working space, said groovesin the disc being regularly distributed about the circumference thereofin such manner that the angle enclosed by radial planes passing throughthe center of two adjacent grooves and the axis of the disc is equal tono greater than half of the angle enclosed by two planes each passingthrough the axis of the disc and one of which passes through the end ofthe wall part of the housing forming the boundary of the working spacewhich communicates within the inlet aperture and the other passesthrough the end of said wall part which communicates with the outletaperture, equal discharge grooves provided on each cylindrical wall partwhich forms a boundary for a working space communicating at its endswith inlet and outlet apertures, said discharge grooves extending in thecircumferential direction over a distance equal to the arc length of thecylindrical wall part diminished by twice the distance between the vanesmeasured on the same diameter as that of the relative wall part, saidgrooves being arranged so that when a vane passes thereacross theresistance to flow across said vane is substantially equal to half theresistance to flow across a vane which contacts the track of the wallpart in which no discharge grooves are arranged.